The process of picking cotton and removing seeds, trash and other foreign materials from the seed cotton is well known. Freshly picked seed cotton is transported from the field to a cotton gin. The cotton gin has apparatus for receiving the seed cotton, removing the seeds from the long cotton fiber or lint, cleaning the lint, and pressing the lint into bales for sale and further processing.
Central to this process is a saw type gin stand (referred to herein as a gin saw stand or gin). The gin saw stand separates the cotton fiber from the seeds. Before the seed cotton is fed into the gin saw stand, it is processed with other apparatus to remove heavier foreign materials such as rocks and larger sticks, etc., and dried to desired moisture levels. After drying and cleaning, the seed cotton is fed at a controlled rate into a gin saw stand. From the gin saw stand, the cotton fiber is next transported to lint cleaners for further cleaning or processing before bailing.
A commercial gin saw stand which is currently in use is shown in cross section in FIG. 1. Referring to the figure, conventional gin saw stands 10 typically comprise an inlet cotton chute 11 wherein the cotton is deposited. A gin saw cylinder 12, composed of a large number of spaced apart circular blades 13 rotating having serrated outer edges 15 about a common axis 14, is combined with operably associated ribs 26 positioned between the blades 13 of the saw in order to strip the lint from the seed.
Delivery of the seed cotton into contact with the teeth of the first saw is assisted by a rotating toothed cylinder, referred to as the picker roller 21, which throws the cotton from the inlet cotton chute 11 onto the saw 12. This picker roller 21 is generally positioned with its axis 22 approximately lateral to the axis 14 of the saw 12, with its outer periphery 23 spaced apart from the serrated outer periphery 15 or teeth of the saw 12. The locks of cotton are drawn upwardly by the saw 12, through a passage called the seed discharge shaft 31 and into the lower portion of a roll box 25 positioned above the axis 14 of the saw 12 where the seeds with attached cotton accumulate in a large mass. This mass of seeds and/or seed cotton is commonly referred to as the roll or seed roll (not shown in FIG. 1). Most of the interior of the seed roll is made up of lint-free seed, and the exterior primarily comprises partially ginned seed and un-ginned seed.
The roll box 25 is typically of somewhat distorted cylindrical configuration and its structure is shaped by the exposed, inwardly facing (relative to the roll box) surfaces of a plurality of different members of the gin saw stand 10, such as, in the illustrated example, the upper portions 26a of the ginning ribs 26, the upper rib support 34, one or more upper gin-side sheet members 38 (which may further comprise the inner surface 37 of door member 36), one or more concave partition or sheet members 39 of the breast 18 and adjustable sheet member 20. Prior art gin saw stands 10 did employ an adjustable sheet member 20 though previously such sheet members have had a very limited degree of actuation, limited to the function and path of travel as that obtained with the cam shaft assembly as discussed herein. Prior art sheet members 20 did not serve the function of retaining the seed roll with in the roll box as is accomplished by the greater range of motion of the seed roll retaining member of the present invention (discussed below).
In some prior art gin saw stands (not shown), the roll box may also comprise an alternate additional set of ginning ribs for one or more additional saw cylinders.
While the roll box door member 36 of some prior art gin saw stands 10 do not form part of the roll box 25, it is not uncommon for at least a portion of the roll box 25 to be formed by the concave inner surface 37 of the roll box door member 36 as illustrated in FIG. 1. Typically there is a gap or space 35 in the upper portion of the roll box 25 to allow the seed roll to be viewed or even touched as the gin is operating. It will be noted that at the gap 35, the seed roll will maintain its generally circular shape because the centrifugal force will tend for it to move horizontally at this point, but gravity and the cohesive qualities of the fibers within the exterior regions of the seed roll tends to pull it down.
As gin saw capacities have increased, gin saw stands have become wider. At the same time, the increased capacities and density of the seed rolls within these larger machines have resulted in the need for the reinforcement of the roll box surfaces shaping the seed roll. As a result, the surfaces forming the roll box, including the roll box door member 36, have been made sturdier and more rigid, and thus thicker and heavier. This has resulted in roll box doors 36 that are cumbersome and may require the efforts of two or more individuals to open.
The actual separation of the seed from lint takes place in the roll box 25 of the gin saw stand 10. In the prior art gin saw stand 10 illustrated in FIG. 1, a set of ribs, referred to as the ginning ribs 26, are located in the spaces between the blades 13 of the saw 12 at the downstream end of the roll box 25, and extend from a position above the periphery 15 of the saw 12 downward through the spaces between the blades 13 to near or below the bottom of the saw 12. Cotton fibers in the roll box 25 are caught by the teeth of the first saw and passed toward the ginning ribs 26. As the teeth of the saw 12 pass between the ginning ribs 26, they pull the lint from the seeds, which are too large to pass between adjacent ribs 26. The seed-free lint proceeds past the ginning ribs 26 where it is removed from the teeth of the blades 13 by the faster moving brushes of the doffing brush 27 and passed out of the gin stand 10 through the doffing outlet 29 for transferral to the lint cotton cleaners and/or the battery condenser and bailing press depending upon the design of the installation.
As the seeds in the seed roll become substantially free of lint or in a substantially completely “ginned” state, they are of appropriate size and character to pass gravitationally downward adjacent the ginning ribs 26 between the saw blades 13 through the seed discharge shaft 31 and into a seed collection area 32 in the front lower portion of the gin saw stand 10, to be picked up by the usual seed discharge screw conveyor 33 and delivered to the discharge point (not shown). Lint-free seeds are not held firmly within the surface of the seed roll and often escape the seed roll along the relatively sharp curve or bulge in the seed roll that is formed at the bottom of the seed roll over the seed discharge shaft 31 immediately prior to being pulled upward by the periphery 15 of the saw 12. The seed discharge shaft 31 is defined by the space between the ginning ribs 26 and the closest, lower breast-side edge 45 of the roll box 25. Note, however, that when the breast 18 is in the closed position, the blades 13 extend through the ginning ribs 26 and into the seed discharge shaft 31.
In contrast to the substantially lint-free seeds, seeds which retain cotton fibers thereon generally remain on the surface of the mass of seeds and seed cotton (the seed roll) in the roll box 25, awaiting to be caught by the saw 12 and repeat the ginning operation.
In some models of gin saw stands, one or more rotating agitators 75 transversely spanning the gin saw stand 10 substantially parallel to the axis 14 of the saw 12 and having a serrated outer edge or periphery 76, have been placed in the roll box 25 to assist the gin saw 12 in turning the roll of material within the roll box 25. Typically, such agitators 75 comprise a plurality of discs 77 about the agitator axis 78, said discs 77 having serrated teeth about the periphery 76 and being canted at an angle relative to the gin saw blades 13 to cause some side to side action within the seed roll. The agitator 75 spins in a direction counter to the direction of the spinning saw 12. The agitator 75 is typically not located in the exact center of the roll box cavity 25, but is somewhat offset, and its periphery 76 is closer to the periphery 15 of the saw 12 than to the other surfaces defining the roll box 25. In some designs (not shown in FIG. 1), the agitator axis 78 further comprises or may be replaced by a perforated tube containing an auger which provides an additional path for seed to leave the seed roll.
The gin stand 10 typically comprises a casing or housing comprising a main gin frame 17 supporting the gin saw cylinder 12 and doffing brush 27, and a separable front, forwardly movable breast 18 including inlet cotton chute 11 and the supports for ginning ribs 26, picker roller 21, roll box door member 36, and (if any) agitator 75, permitting the breast structure 18 to be drawn away from the main gin frame 17. The breast 18 is typically attached to the main gin frame 17 in such a manner that it may be pulled away from the frame 17. In the prior art gin saw stand 10 shown in FIG. 1, the breast 18 is moved away from the frame 17 substantially laterally along the surface of an integrated rail or track 49 on opposing sides of the frame 17 by powered gears or a pneumatic cylinder (not shown in FIG. 1) or other common means. Another typical configuration is shown in FIG. 2 wherein the breast 18 is attached to the frame 17 at a pivot point 19 located near the front bottom of the main gin frame 17 so that the breast 18 may be tilted away from the main gin frame 17, thereby creating greater space between the breast 18 and the main gin frame 17 at the top of the breast 18 than at the lower regions. The breast 18 is typically attached to the main gin frame 17 at the top by a pneumatic or hydraulic cylinder 47 to power the movement of the breast between a fully-open, non-ginning position and closed, ginning position.
Moving or tilting the breast 18 or otherwise withdrawing it from the main gin frame 17 may be used as a method of interrupting the ginning process instead of stopping the saw 12 from turning. As the breast 18 is withdrawn to a fully-open position, the ginning ribs 26 move even with, or preferably beyond or outside the periphery 15 of the saw 12, thereby preventing the saw cylinder 12 from removing lint from the seed roll 25. This is important because it is much more efficient to simply move the breast 18 away from the main gin frame 17 than to stop the relatively massive saw cylinder 12 from spinning, then having to bring it back up to speed when the ginning process is to be re-started. As a practical matter, it is impossible to restart a motionless saw 12 with a full seed roll if the breast 18 is in the ginning position. The saws will encounter so much resistance, that the motor cannot start without over loading the motor starter.
Over the years, the capacities of gin saws 12 have increased, with the stands becoming wider and wider and with higher density seed rolls. As capacities have increased, the width of the seed discharge shaft 31 between the ginning ribs 26 and the lower, breast-side edge 45 of the roll box 25 immediately above the picker roller 21 has also increased to allow more cotton into the roll box and more ginned seed out. A drawback to this approach is that when the breast 18 is moved away from the main gin frame 17, an relatively larger open gap is created between the lower, breast-side edge 45 of the roll box 25 and the ginning ribs 26 as the blades 13 of the saw 12 are withdrawn from between the ginning ribs 26. When in operation, this gap is occupied by the portion of the saw blades 13 that extends through the ginning ribs 26 and the spin of the saw blades 13 provides an upward current in the mass of seeds and seed cotton in the roll box such that there is little likelihood that seed cotton will fall down the seed discharge shaft 31. However, as progressive models of saw stands have moved the lower, breast-side edge 45 of the roll box 25 higher and higher above the picker roller 21 to allow for greater cotton flow, the width of the open gap created when the breast 18 is opened has also increased because as seen in FIG. 1, the ginning ribs 26 typically have a curvature that mirrors an arc of the periphery 15 of the circular saw blades 13. Therefore, the higher the bottom edge 45 of the seed box 25 is positioned relative to the periphery 15 of the saw 12, the further the ginning ribs 26 curve away from the bottom edge 45 at that same relative height.
The larger gaps created when the breast 18 is opened combined with the bigger and more dense seed rolls in current gin saw stands, has led to an increase in the occurrence of seed roll breakage, with parts of the roll, and sometimes even the entire seed roll, including un-ginned seeds with usable cotton, breaking off and falling into the seed discharge shaft 31 when the breast 18 is opened because it is no longer supported by the saw 12 or the lower edge 45 of roll box 25 and/or seed vanes 40 (if any). Obviously, the loss of un-ginned cotton down the seed discharge shaft 31 is undesirable in that it is either wasted or reclaiming it requires a separate operation, resulting in lower productivity and higher expense.
Efforts have been made in the past to manipulate the shape of the roll box for the purpose of accelerating the removal of fully ginned seed from the seed roll. An example is shown in U.S. Pat. Reg. No. 4,974,294 issued to Vandergriff entitled Cotton Gin Seed Vanes and Seed Roll Box, wherein a set of spaced-apart vanes are attached to an adjustable finger shaft thereby allowing for the increased width of the seed passage which aids in increasing the rate of discharge of ginned seeds. The vanes extend from the finger shaft mounted across the breast below the bottom edge of a flat or planar surface of the roll box. The vanes extend from the breast into the seed passage when the breast is closed for operation to prevent the seed roll from sagging too deeply into the seed passage and to purposefully slice into the seed roll with the intent of rupturing the lint-covered surface of the seed roll to more easily allow ginned seeds from the interior of the seed roll to escape. The vanes are spaced apart on the finger shaft to allow ginned seed to fall between them down through the seed passage.
A thorough description of a variety of commercially available gin saw stands and their operation is provided by Anthony and Mayfield (ed.), Cotton Ginner's Handbook, Agricultural Handbook No. 503, United States Department of Agriculture, Agricultural Research Service, Washington, D.C., 1994, the contents of which are incorporated in their entirety by reference herein.